Smart wearable devices, such as smart watches, bracelets, glasses, and necklaces, are becoming more and more popular. The existing smart necklaces in the related art include a lanyard detachably coupled to a necklace body. The lanyard is wrapped around a user's neck, and the necklace body may be used while walking or running. However, the main body of the smart necklace is prone to rotate relative to the lanyard when the main body is not held in place.